Can you advise me on choosing some trailing bedding plants for balcony wall planters that are in shade for most of the day? This year we planted petunias, but they did not fare very well after the first month.

Summer bedding favours the south-facing. Most of the bedding in the garden centre in spring wants sun, so I am not surprised that you were tempted by a wrong 'un. Come winter, though, the field is levelled. Then, it's pansies, violas and cyclamen for all, and - lucky you - they are quite content in shade. Your trailing element will be ivy, but that needn't be so dull if you seek out those with variegation or unusual leaf shapes (I especially like the bird's foot ivy, Hedera helix 'Pedata'). If you're not sick of violas by next summer, combine flower and form with some friolina violas, a revolution in viola breeding, or so I am reliably informed, with metre-long cascades of tiny, scented flowers. They are available as small plants from Thompson & Morgan (0844 248 5383, thompson-morgan.com).

Sadly, we have just removed a large robinia tree that was planted about 3m away from our kitchen window (at the limit of our front garden) to block out a neighbouring ugly garage wall. Can you suggest an alternative small tree?

I can't imagine the robinia was doing much of a job of hiding the wall - just a thin strip of it behind the trunk, surely? A shrub might be more the thing for such blocking intentions; they can be made to look awfully tree-like with judicious pruning. Hamamelis (or witch hazel) might fill the space perfectly, and if you go for 'Jelena' or 'Diane', it will give you autumn colour as well as winter flowers. Crab apples are handsome and compact, with lovely, bushy growth to cover the wall, blossoms in spring and fruit in winter to distract you from that annoying view.